C#调用Windows系统自带虚拟键盘，可以通过以下方法。

1、添加外部引用

private const Int32 WM_SYSCOMMAND = 274;private const UInt32 SC_CLOSE = 61536;[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]private static extern bool PostMessage(IntPtr hWnd, int Msg, int wParam, int lParam);[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]private static extern bool PostMessage(IntPtr hWnd, int Msg, uint wParam, uint lParam);[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]private static extern bool PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]private static extern int RegisterWindowMessage(string lpString);

打开虚拟键盘方法：

public  void ShowKey(){var commonFilesPath = Environment.GetFolderPath(Environment.SpecialFolder.CommonProgramFiles);//程序集目标平台为X86时，获取到的是x86的Program Files，但TabTip.exe始终在Program Files目录下if (commonFilesPath.Contains("Program Files (x86)")){commonFilesPath = commonFilesPath.Replace("Program Files (x86)", "Program Files");}var tabTipPath = Path.Combine(commonFilesPath, @"microsoft shared\ink\TabTip.exe");//var tabTipPath = "C:\\Program Files\\Common Files\\microsoft shared\\ink\\TabTip.exe";if (File.Exists(tabTipPath)){ProcessStartInfo psi = new ProcessStartInfo{FileName = tabTipPath,UseShellExecute = true,CreateNoWindow = true};Process.Start(psi);//Process.Start(@"C:\windows\system32\osk.exe");UnityEngine.Debug.Log("OK");}}

关闭键盘方法：

 public  void HideKey(){IntPtr TouchhWnd = new IntPtr(0);TouchhWnd = FindWindow("IPTip_Main_Window", null);if (TouchhWnd == IntPtr.Zero)return;PostMessage(TouchhWnd, WM_SYSCOMMAND, SC_CLOSE, 0);}

经测试使用该方法调用win8/10系统都没问题。

实现效果：